1. Field of the Invention
The present invention relates to an electronic component, and more particularly to an electronic component in which dielectric layers and capacitor conductors are stacked.
2. Description of the Related Art
In an electronic component in which dielectric layers and capacitor conductors are stacked, when an AC voltage is applied to the electronic component, electric-field-induced strains are generated in the dielectric layers due to the applied voltage. Those electric-field-induced strains vibrate a substrate on which the electronic component is mounted, thus generating sounds called “vibration noise”. As a related-art electronic component aiming to reduce the “vibration noise”, there is known a multilayer ceramic capacitor disclosed, for example, in International Publication No. 2007/020757. FIG. 7 is a sectional structural view of a multilayer ceramic capacitor 500a disclosed in International Publication No. 2007/020757.
As illustrated in FIG. 7, the multilayer ceramic capacitor 500a includes a capacitor body 502, an inner electrode 504, and outer electrodes 506 and 508. The capacitor body 502 is constituted by stacking a plurality of dielectric ceramic layers. The inner electrode 504 has a rectangular shape and constitutes a capacitor by being stacked together with the dielectric ceramic layers. The outer electrodes 506 and 508 cover end surfaces of the capacitor body 502, the surfaces being positioned at both ends thereof in a lengthwise direction. Furthermore, the outer electrodes 506 and 508 have shapes folded to partly extend over lateral surfaces adjoining with the end surfaces of the capacitor body 502.
In the multilayer ceramic capacitor 500a, cutouts A1-A4 are formed in the inner electrode 504 at respective locations near edges B1-B4 of the outer electrodes 506 and 508 in order to reduce the “vibration noise”. With such a structure, the stacked inner electrodes 504 are not positioned opposite to each other in the cutouts A1-A4. Therefore, generation of the electric-field-induced strains in the dielectric ceramic layers is suppressed in regions corresponding to the cutouts A1-A4, and generation of vibrations in the outer electrodes 506 and 508 is also suppressed. As a result, the vibrations are inhibited from being propagated to the substrate through the outer electrodes 506 and 508.
In the multilayer ceramic capacitor 500a illustrated in FIG. 7, however, it is difficult to sufficiently reduce the “vibration noise”. In more detail, the inner electrode 504 is positioned close to the outer electrodes 506 and 508 in not only the cutouts A1-A4, but also in sides C1-C4 thereof, which are positioned outside the edges B1-B4. Therefore, when the electric-field-induced strains are generated in the dielectric ceramic layers near the sides C1-C4, vibrations are caused in the outer electrodes 506 and 508. Consequently, the “vibration noise” is generated.
International Publication No. 2007/020757 further discloses a multilayer ceramic capacitor 500b illustrated in FIG. 8. FIG. 8 is a sectional structural view of the multilayer ceramic capacitor 500b disclosed in International Publication No. 2007/020757. It is to be noted that similar constituent elements in the multilayer ceramic capacitor 500b to those in the multilayer ceramic capacitor 500a are denoted by the same reference signs.
In the multilayer ceramic capacitor 500b, as illustrated in FIG. 8, the inner electrode 504 has a cross shape. More specifically, the cutouts A1-A4 are formed to extend up to both the ends of the inner electrode 504 in the lengthwise direction thereof. With such a structure, the distance between the inner electrode 504 and each of the outer electrodes 506 and 508 is increased. As a result, even when electric-field-induced strains are generated in the dielectric ceramic layer sandwiched between the inner electrodes 504, generation of vibrations in the outer electrodes 506 and 508 is suppressed. Thus, generation of the “vibration noise” is suppressed.
However, the cutouts A1-A4 of the multilayer ceramic capacitor 500b illustrated in FIG. 8 have larger sizes than the cutouts A1-A4 of the multilayer ceramic capacitor 500a illustrated in FIG. 7. Accordingly, a capacitance value of the multilayer ceramic capacitor 500b is smaller than that of the multilayer ceramic capacitor 500a. 